106 Proceedings of the Ohio State Academy of Science 



9. Flowers not in aments but variously clustered, sometimes 

 solitary. 12. 

 10. Leaves simple. 11. 



10. Leaves odd-pinnate ; fruit a nut inclosed in a husk. JUG- 



LANDACEAE. 



a. Pith of twigs in transverse plates: husk indehiscent; 



nut rugose. Juglans. (14). 

 ;a. Pith solid; husk at length s|)litting into segments, 



nut smooth or angled. Hicoria. (15). 



11. Both staminate and carpellatc flowers in aments; sap not 



milky. Betulaceae. 

 a. Staminate flowers solitary in the axil of each bract, 

 without a calyx; carpellate flowers with a calyx, b. 



a. Staminate flowers 3-6 in the axil of each bract, with a 



calyx ; carpellate flowers without a calyx, c. 



b. Fruiting bractlet flat, 3-cleft and incised ; nut small. 



Carpinus. (16). 



b. Fruiting bractlet bladder-like, closed, membranous; 



nut small. Ostrya. (17). 



c. Stamens 2; fruiting bracts 3-lo':)ed or entire, decidu- 



ous. Betula. (18). 

 c. Stamens 4; fruiting bracts woody, persistent; pith 

 3-angled. Alnus. (19). 



II. Carpellate flowers subtended by an involucre which becomes 

 a bur or cup in fruit ; staminate flowers in aments, or capi- 

 tate. Fagaceae. 

 a. Staminate flowers capitate ; nut triangular. Fagus. 

 (20). 



a. Staminate flowers in slender aments ; nut rounded, b. 



b. Carpellate flowers 2-5 in each involucre, which be- 



comes prickly in fruit. Castanea. (21). 

 b. Carpellate flower i in each involucre, which consists 

 of numerous scales. Quercus. (22). 

 II. Trees with alternate leaves and milky sap; ovules pendulous. 



MoR.\CEAE. 



See 15 below. 



